How to mark out foundations using a brick line?

Step 1 – Measure dimensions

You will need to know the dimensions of the building that is being constructed. This includes all external walls and internal load-bearing walls. Precision is paramount.

Step 2 – Mark points

Once you know the dimensions of your building’s walls, mark the external corner points by inserting stakes into the ground. It is important that the lengths of the walls are marked exactly and the stakes positioned appropriately.

Step 3 – Set up batter-boards

At right angles to your all your corner points, insert batter-boards. It is important to make sure that they are firmly planted and secure, as any movement may affect the position of your brick lines later on. You will need eight batter-boards for a four-walled structure.

What is a batter-board?

A batter-board is a simple wooden structure that is used to secure a brick line. It is made simply by nailing a piece of wood across the faces of two stakes. The cross bar of wood needs to be at least as wide as your foundations will be.

Step 4 – Suspend brick lines (external)

Attach a brick line to the cross bar of your batter-board. Extend the brick line and attach it to the opposite batter-board, making sure that the brick line is taut and perfectly level. Repeat this process until all the external foundation guidelines have been made.

Step 5 – Check alignment

At this point you can check your alignment by hanging a plumb-bob from the point at which your brick lines cross. If the plumb-bob hangs directly above the centre of your stake then they are correctly aligned.

Step 6 – Suspend brick lines (internal)

Once you have the external boundaries of your foundations marked out, you can now set about marking the internal boundaries. All you have to do is attach another brick line and run it parallel to the external line. Extend the brick line to its opposite batter-board and attach it there, making sure the line is taut and level. The distance between your external and internal lines should be the appropriate width for your foundations.

Step 7 – Dig trench

With all the guidelines in place, you can now dig out a trench directly below and between these lines. The trench should be dug as accurately as possible and should be deep enough to support your building’s walls. This is usually up to 1 metre deep but differs depending on the height of your walls. To be sure, check with building regulations.

Step 8 – Fill with concrete

Once you have dug out a trench to the required depth, fill with concrete and allow several days for it to harden.